President Obama speaks during a press conference with British Prime Minister David Cameron at the White House on Monday. / Jim Watson, AFP/Getty Images

by David Jackson, USA TODAY

by David Jackson, USA TODAY

President Obama and his aides are trying to put as much distance as possible between themselves and the Internal Revenue Service - and with good reason.

Using the IRS for political purposes brought down one president - Richard Nixon - and has hurt the historical reputations of other chief executives.

"You get burned, and these people don't want to play with fire," presidential historian Stephen Hess said.

The current allegations against the IRS - that it targeted conservative groups with "Tea Party" and "Patriot" in their names - are "outrageous" and cannot be tolerated if true, Obama said at a brief news conference on Monday.

Noting that the IRS is an "independent agency," Obama said the tax laws must be applied in "a neutral and non-partisan way."

Presidents often need distance from the IRS because some of the history between the White House and the agency has been less than inspiring.

David Burnham, author of the book A Law Unto Itself: The IRS and the Abuse of Power, has written that presidents back to at least Herbert Hoover have made questionable use of the organization.

Burnham and historians have accused President Franklin Delano Roosevelt of having the IRS look into a number of his critics, including Sen. Huey Long, Father Charles Coughlin and Hoover Treasury Secretary Andrew Mellon. (Long may have been planning to challenge Roosevelt in 1936, but was assassinated a year before the election.)

There is also evidence that a future president - then-U.S. Rep. Lyndon Johnson - persuaded Roosevelt to shut down an investigation of some important Johnson backers.

In his book Power to Destroy: The Political Uses of the IRS from Kennedy to Nixon, the late historian John A. Andrew III described a number of abuses during the 1960s and '70s.

President Kennedy's administration - with his apparent knowledge - authorized an "Ideological Organizations Project" that targeted conservative organizations, such as the John Birch Society. Those allegations resemble the current ones, though Obama and aides deny any knowledge or involvement.

During his years as president, Johnson is accused of promising tax favors in exchange for votes, Andrew wrote.

Most of these incidents went undetected at the time.

So it fell to Richard Nixon to provide the starkest object lesson for predecessors tempted to use the Internal Revenue Service for political purposes.

Nixon aides developed the notorious "enemies list" - from political leaders to think tanks, reporters to entertainers - so that they could be targeted by the IRS.

When the House Judiciary Committee recommended Nixon's impeachment in 1974, one of the counts said he and subordinates sought "to obtain from the Internal Revenue Service, in violation of the constitutional rights of citizens, confidential information contained in income tax returns for purposes not authorized by law."

Nixon resigned before the full House could hold an impeachment vote.

Susan Long - who along with Burnham is co-director of the Transactional Records Access Clearinghouse at Syracuse University - said Nixon created a broad, systematic political use of the IRS, rather than use the agency on a case-by-case basis.

"It was a whole program - an 'enemies list' - that the IRS had," Long said.

Given this dark history, many targets of IRS audits still suspect political motives.

Critics of President Clinton - including Paula Jones, whose sexual harassment lawsuit led to the Monica Lewinsky scandal - accused that administration of ordering audits in retaliation.

Clinton aides denied it.

"We may do some dumb things from time to time, but we are not certifiably insane," said Clinton spokesman Mike McCurry at the time. "The IRS, and the IRS solely, is the one that makes decisions about the enforcement of tax laws."

Stan Collender, a partner at Qorvis Communications who studies financial and political issues, says the IRS represents the rawest of government power - the power to tax - and presidents are wise not to abuse it.